Plant α-glucan phosphatases SEX4 and LSF2 display different affinity for amylopectin and amylose

Casper Wilkens, Kyle D. Auger, Nolan T. Anderson, David A. Meekins, Madushi Raththagala, Maher Abou Hachem, Christina M. Payne, Matthew S. Gentry, Birte Svensson

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    The plant glucan phosphatases Starch EXcess 4 (SEX4) and Like Sex Four2 (LSF2) apply different starch binding mechanisms. SEX4 contains a carbohydrate binding module, and LSF2 has two surface binding sites (SBSs). We determined KDapp for amylopectin and amylose, and KD for β-cyclodextrin and validated binding site mutants deploying affinity gel electrophoresis (AGE) and surface plasmon resonance. SEX4 has a higher affinity for amylopectin; LSF2 prefers amylose and β-cyclodextrin. SEX4 has 50-fold lower KDapp for amylopectin compared to LSF2. Molecular dynamics simulations and AGE data both support long-distance mutual effects of binding at SBSs and the active site in LSF2.
    Original languageEnglish
    JournalFEBS Letters
    Issue number1
    Pages (from-to)118-128
    Number of pages11
    Publication statusPublished - 2016


    • Affinity gel electrophoresis
    • Carbohydrate binding domain
    • Like Sex Four2
    • Starch Excess 4
    • Surface binding sites
    • Surface plasmon resonance

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